Vascular Access The Alpha and Omega of CRRT Rick Hackbarth MD Division of Pediatric Critical Care Grand Rapids, Michigan

Vascular Access Wisdom “If you don’t have good access you might as well go home!”

Vascular Access The portal from patient to circuit Affects circuit life Lost circuits may expose patients to more transfusions and frustrates staff Affects clearance Lower blood flow rates and hemofiltration rates More downtime

Vascular Access Two questions to be answered- What size catheter to use? Where to put it?

Vascular Access Wisdom “Size matters!”

Vascular Access 8l Pousielle’s Law- Q = ∆Pπr4 Smaller diameters offer greater resistance to flow Longer lengths offer greater resistance to flow Decreasing the diameter by 1/5th is the same as doubling the length (roughly a 2 French size difference) Q = ∆Pπr4 8l

Vascular Access ppCRRT Registry Access Study 13 Pediatric Institutions 376 patients 1574 circuits Circuit survival by Catheter size, site, and modality Hackbarth R et al: IJAIO 30:1116-21, 2007

Vascular Access Hackbarth R et al: IJAIO 30:1116-21, 2007

Hackbarth R et al: IJAIO 30:1116-21, 2007

Vascular Access 1st 72 hrs of circuit life only Shorter life span for 7 and 9 French catheters (p< 0.002) Hackbarth R et al: IJAIO 30:1116-21, 2007

Hackbarth R et al: IJAIO 30:1116-21, 2007

Vascular Access Wisdom “Location, location, location!”

Vascular Access “Location, location, location!” Options: Femoral vein Subclavian vein Internal Jugular vein

Vascular Access “Location, location, location!” Femoral Vein Pros: Accessible under almost any conditions Easier to maintain hemostasis Cons: Potential for kinking More recirculation Thrombosis Problematic flow with increased abdominal pressures

Vascular Access “Location, location, location!” Subclavian Vein Pros: Shorter catheter/better flow Less recirculation Cons: Potential for kinking Difficult hemostasis Potential for venous narrowing Less accessible with cervical trauma

Vascular Access “Location, location, location!” Internal Jugular Vein Pros: Shorter catheter/better flow Less recirculation Cons: Difficult hemostasis Less accessible with cervical trauma Catheter length problematic in small infants

Vascular Access Highly variable position of the IJ vein Ultrasound can be quite helpful Maecken T et al: CCM 35: S178-85, 2007

Hackbarth R et al: IJAIO 30:1116-21, 2007

Vascular Access Survival favors IJ Location (p< 0.05) Hackbarth R et al: IJAIO 30:1116-21, 2007

Vascular Access Wisdom “It’s déjà vu all over again.”

Vascular Access Recirculation More of an issue in femoral catheters especially shorter than 20 cm Is this really a practical concern with 24/7 clearance? Catheter proximity may be a bigger issue

Vascular Access Note the relationship of the line tips.

Vascular Access Catheter proximity Inadvertent removal of infusions Circuit clotting with platelet transfusions Entraining calcium into the circuit

Vascular Access Wisdom “You can’t always get what you want, but you might get what you need!”

Vascular Access Catheter Specifications French Size 5 7 8 10 12 Flow Rate (ml/min) ? 80-100 150-200 250-300 285-330

Vascular Access Catheter Specifications French Size 5 7 8 10 12 Diameter (mm) 1.67 2.3 2.7 3.3 4.0

Vascular Access Steinberg et al: Catheterization and Cardiovascular Diagnosis 27: 197-201, 1992

Vascular Access Pousielle’s Law- Q = ∆Pπr4 8l

Vascular Access

Vascular Access

Vascular Access Differing Perspectives on the ICU Patient It was six men of Indostan To learning much inclined, Who went to see the Elephant (Though all of them were blind), That each by observation Might satisfy his mind. John Godfrey Saxe The Blind Men and the Elephant

Vascular Access Differing Perspectives on the ICU Patient And so these men of Indostan Disputed loud and long, Each in his own opinion Exceeding stiff and strong, Though each was partly in the right, And all were in the wrong! John Godfrey Saxe The Blind Men and the Elephant

Vascular Access

Vascular Access

Vascular Access

Vascular Access

Vascular Access Two questions to be answered- What size catheter to use? Where to put it?

Vascular Access What size catheter should we use? Don’t use a 5 French catheter. Choose the largest diameter that is safe for the child. Choose the smallest catheter that will achieve the necessary flow easily. Choose the the minimum length to position the tip for optimal flow. In the femoral position, longer catheters will minimize recirculation

Vascular Access Where should the catheter go? What sites are available? Are there anatomic or physiologic constraints? Which vessel is optimal for the catheter size? Is the patient coagulopathic? Consider patient mobility and risk of kinking. Is there elevated intra-abdominal pressure?

Vascular Access Where should the catheter go? Answer: Internal Jugular vein if possible

Disney Wisdom “I would rather entertain and hope that people learned something than educate people and hope they were entertained.”